Maybe you should _____________.

                                                                                                                                                          [ ]

A. call on him          

B. call up him          

C. call him up

D. make a telephone call with him

脚手架上门洞桁架下的两侧立杆（）。

A．应为双立杆，副立杆应高出于门洞口1步 

B．应为单立杆，并符合有关技术要求 

C．应为双立杆，副立杆应高出于门洞口的1~2步 

D．应为双立杆，主立杆应高出于门洞口的1~2步